President Donald Trump's poll numbers have slightly declined, but he remains more popular than Hillary Clinton.
In a NBC/Wall Street Journal survey conducted between Aug. 5 and 9, 36 percent of respondents said they had either very or somewhat positive feelings about Trump, Politico reports.
Only 30 percent said the same for Clinton, Trump's challenger in the 2016 presidential election.
Other polls show that frustration with Trump is rising among some groups. A YouGov survey conducted from July 13 to 24 found that 22 percent of voters who backed Barack Obama in 2012 and Trump in 2016 were dissatisfied with Trump's performance. This was significantly higher than the level of dissatisfaction among Trump voters overall, The Washington Post notes.
The survey also noted that 20 percent of Trump voters were unsure whether they would stick with their party in the next election. This uncertainty rose to 44 percent among those who voted for Obama in 2012 and Trump in 2016.
In the NBC poll, 53 percent said they had very or somewhat negative feelings about Clinton, while 52 percent felt the same way about Trump.
Trump's approval rating from the 1,200 participants was 40 percent, the same as it was in June when NBC/Wall Street Journal carried out its last poll.
While Clinton remained relatively quiet during Trump's first months in office, the release of her new book "What Happened" has made headlines.
"I go back over my own shortcomings and the mistakes we made," Clinton writes of her 2016 campaign, according to CNN. "I take responsibility for all of them. You can blame the data, blame the message, blame anything you want -- but I was the candidate. It was my campaign. Those were my decisions."
Clinton's book also contains sharp criticism of Trump and what he has done as president.
In addition, she acknowledges that she miscalculated the political environment during the campaign.
"I think it's fair to say that I didn't realize how quickly the ground was shifting under all our feet," she added. "I was running a traditional presidential campaign with carefully thought-out policies and painstakingly built coalitions, while Trump was running a reality TV show that expertly and relentlessly stoked Americans' anger and resentment."
But she also admitted that she cannot explain everything, writing: "What makes me such a lightning rod for fury? I'm really asking. I'm at a loss."
Clinton also blamed some others for contributing to her defeat, including her Democratic primary challenger Sen. Bernie Sanders of Vermont and James Comey, the former FBI director who investigated Clinton's use of a private email server.